Start using CSS3 gradients in your themes
Here are two generators to create gradients with CSS (say goodbye to those Photoshop image slices).
Check out Ultimate CSS Gradient Generator to grab cross-browser friendly CSS for use in your themes. It allows for a high level of control with some helpful presets.
Also visit Microsoft’s gradient generator. The team have made a web-standard friendly generator and it’s very easy to use. One of the best features in this tool is the ability to paste existing markup from the generator.